Debone toast, cut into rhombs and roast in hot fat until golden brown. In the meantime peel onions and cut them into half rings. Drain artichokes and olives. Cut the artichokes in half.
Remove the olives from the stone. Cut melon in half and remove seeds. Cut out the flesh with a ball cutter. Cut the ham into strips. Wash the salad and pluck into bite-sized pieces. Mix the salad with the prepared ingredients.
Drain the mandarins and mash them. Mix with mayonnaise and ketchup. Pour some salad dressing over the salad. Put the rest of the sauce in a small bowl, sprinkle with tarragon and serve separately.